Ken Balcomb: SRKW demographic update

First there was Mike Bigg. Early census effort started in 1976 and was motivated by concern about the captures for aquariums which took out about 50 animals. 1976-1984 habitat use was very similar to current critical habitat! Most encounters May-October, with J pod present year-round.

Ken and Mike worried about how to ID babies. They discovered that eye patches were unique. J44 has a nice Moby Dick patch and has been seen with J 17 (possible mother). J45 was first seen by Jeanne.

The population was about 70 when they started and got up to close to 100 before declining in the 1990s. Ken took news of the decline to the Hawaii meeting with the “God Squad.”

In 2006, the matrilines had about 24 reproductive-aged females. Looking forward 5-10 years, there is potential for about 19 babies, but about 40% will die as neonates. So there is potential for growth, but you have to feed them and there is the question of rising concentrations of PCBs and PBDEs, etc.

L60 died at Long Beach, WA in April, 2002, at age 30. Her ovaries (corpus albicans) indicated she had been pregnant about 7 times, though she had only two surviving offspring. Was she too starved to support those babies, or were contaminants the culprit?

Both L and K pod have been sighted as far south as Monterrey during the winter. J pod has been seen as far south as Newport, Oregon. John Ford detected J pod at N end of Queen Charlottes and Spong has reported southern residents returning through Johnstone Strait.

Ford et al, 2005 showed that decline in both N and S residents was correlated with W Coast Chinook stocks. Every day from May to October, there were 70 seiners working the west side of San Juan Island. 595,000 Chinook were caught each year back then and that’s about what we need to feed the southern residents.

We need to recover Chinook stocks in the Pacific Northwest if we want to keep southern residents!